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At least 865 records · Page 48Linked to original sources
USGS2011

Value of a dual-polarized gap-filling radar in support of southern California post-fire debris-flow warnings

A portable truck-mounted C-band Doppler weather radar was deployed to observe rainfall over the Station Fire burn area near Los Angeles, California, during the winter of 2009/10 to assist with debris-flow warning decisions. The deployments were a component of a joint NOAA–U.S. Geological Survey (USGS) research effort to improve definition of the rainfall conditions that trigger debris flows from steep topography within recent wildfire burn areas. A procedure was implemented to blend various dual-polarized estimators of precipitation (for radar observations taken below the freezing level) using threshold values for differential reflectivity and specific differential phase shift that improves the accuracy of the rainfall estimates over a specific burn area sited with terrestrial tipping-bucket rain gauges. The portable radar outperformed local Weather Surveillance Radar-1988 Doppler (WSR-88D) National Weather Service network radars in detecting rainfall capable of initiating post-fire runoff-generated debris flows. The network radars underestimated hourly precipitation totals by about 50%. Consistent with intensity–duration threshold curves determined from past debris-flow events in burned areas in Southern California, the portable radar-derived rainfall rates exceeded the empirical thresholds over a wider range of storm durations with a higher spatial resolution than local National Weather Service operational radars. Moreover, the truck-mounted C-band radar dual-polarimetric-derived estimates of rainfall intensity provided a better guide to the expected severity of debris-flow events, based on criteria derived from previous events using rain gauge data, than traditional radar-derived rainfall approaches using reflectivity–rainfall relationships for either the portable or operational network WSR-88D radars. Part of the reason for the improvement was due to siting the radar closer to the burn zone than the WSR-88Ds, but use of the dual-polarimetric variables improved the rainfall estimation by ~12% over the use of traditional Z – R relationships.

Journal of Hydrometeorology↗
USGS2015

A multi-proxy record of hydroclimate, vegetation, fire, and post-settlement impacts for a subalpine plateau, Central Rocky Mountains U.S.A

Apparent changes in vegetation distribution, fire, and other disturbance regimes throughout western North America have prompted investigations of the relative importance of human activities and climate change as potential causal mechanisms. Assessing the effects of Euro-American settlement is difficult because climate changes occur on multi-decadal to centennial time scales and require longer time perspectives than historic observations can provide. Here, we report vegetation and environmental changes over the past ~13,000 years as recorded in a sediment record from Bison Lake, a subalpine lake on a high plateau in northwestern Colorado. Results are based on multiple independent proxies, which include pollen, charcoal, and elemental geochemistry, and are compared with previously reported interpretations of hydroclimatic changes from oxygen isotope ratios. The pollen data indicate a slowly changing vegetation sequence from sagebrush steppe during the late glacial to coniferous forest through the late Holocene. The most dramatic vegetation changes of the Holocene occurred during the ‘Medieval Climate Anomaly’ (MCA) and ‘Little Ice Age’ (LIA) with rapid replacement of conifer forest by grassland followed by an equally rapid return to conifer forest. Late Holocene vegetation responses are mirrored by changes in fire, lake biological productivity, and watershed erosion. These combined records indicate that subsequent disturbance related to Euro-American settlement, although perhaps significant, had acted upon a landscape that was already responding to MCA-LIA hydroclimatic change. Results document both rapid and long-term subalpine grassland ecosystem dynamics driven by agents of change that can be anticipated in the future and simulated by ecosystem models.

The Holocene↗
USGS2006

Temporal-spatial distribution of American bison (Bison bison) in a tallgrass prairie fire mosaic

Fire and bison (Bison bison) are thought to be historically responsible for shaping prairie vegetation in North America. Interactions between temporal-spatial distributions of bison and prescribed burning protocols are important in current restoration of tallgrass prairies. We examined dynamics of bison distribution in a patch-burned tallgrass prairie in the south-central United States relative to bison group size and composition, and burn age and temporal distribution. Bison formed larger mixed groups during summer and smaller sexually segregated groups the rest of the year, and bison selected dormant-season burn patches in the 1st posture growing season most often during spring and summer. Large bison herds selecting recently burned areas resulted in seasonally variable and concentrated grazing pressure that may substantially alter site-specific vegetation. These dynamics must be considered when reintroducing bison and fire into tallgrass prairie because variable outcomes of floral richness and structural complexity are likely depending on temporal-spatial distribution of bison. ?? 2006 American Society of Mammalogists.

Journal of Mammalogy↗
USGS2013

Regional constraints to biological nitrogen fixation in post-fire forest communities

Biological nitrogen fixation (BNF) is a key ecological process that can restore nitrogen (N) lost in wildfire and shape the pace and pattern of post-fire forest recovery. To date, there is limited information on how climate and soil fertility interact to influence different pathways of BNF in early forest succession. We studied asymbiotic (forest floor and soil) and symbiotic (the shrub Ceanothus integerrimus) BNF rates across six sites in the Klamath National Forest, California, USA. We used combined gradient and experimental phosphorus (P) fertilization studies to explore cross-site variation in BNF rates and then related these rates to abiotic and biotic variables. We estimate that our measured BNF rates 22 years after wildfire (6.1–12.1 kg N·ha -1 ·yr -1 ) are unlikely to fully replace wildfire N losses. We found that asymbiotic BNF is P limited, although this is not the case for symbiotic BNF in Ceanothus. In contrast, Ceanothus BNF is largely driven by competition from other vegetation: in high-productivity sites with high potential evapotranspiration (Et), shrub biomass is suppressed as tree biomass increases. Because shrub biomass governed cross-site variation in Ceanothus BNF, this competitive interaction led to lower BNF in sites with high productivity and Et. Overall, these results suggest that the effects of nutrients play a larger role in driving asymbiotic than symbiotic fixation across our post-fire sites. However, because symbiotic BNF is 8–90 x greater than asymbiotic BNF, it is interspecific plant competition that governs overall BNF inputs in these forests.

California↗
USGS2004

Behavioral response of young rainbow trout ( Oncorhynchus mykiss ) to forest fire-retardant chemicals in the laboratory

Fire-retardant chemicals often are applied in relatively pristine and environmentally sensitive areas that are potentially inhabited by endangered or threatened aquatic species. Avoidance of contaminants is an adaptive behavior that may reduce exposure to harmful conditions. We evaluated the avoidance responses of rainbow trout ( Oncorhynchus mykiss ) to concentrations of fire-retardant chemicals and alternate constituent formulations ranging from 0.65 to 26 mg/L. Countercurrent avoidance chambers were used in a flow-through design with receiving water at each end and a drain at the center to create a distinct boundary between treatment water and reference water. Rainbow trout consistently avoided water treated with retardants at all concentrations tested. The magnitude of the avoidance response did not appear to follow a concentration-response relationship, but rather was an all-or-none response.

Environmental Toxicology and Chemistry↗
USGS2020

Selective sediment transport during Hurricane Sandy on Fire Island (New York, USA): Inferences from heavy-mineral assemblages

In October 2012, Hurricane Sandy caused severe erosion on beaches and dunes of Fire Island (New York, USA). Major shoreline changes occurred with erosional dominance in the upper shoreline and aggradation in the lowermost section of the beach due to the deposition of eroded upper beach and dune sediment. Sand laminations with a high concentration of heavy minerals (“black sand laminations”) were observed in three excavated trenches located on a washover terrace and fan on the east side of Fire Island. The mineralogical composition of these laminations reveals the presence of high quantities of magnetite, ilmenite (as opaque minerals), and garnet (as main translucent mineral). These heavy mineral enriched laminations were formed as waves eroded and transported sand from the primary dune and smaller relict dunes under specific hydrodynamic conditions that promoted grain sorting according to differences in size and specific gravity. Based on the concentrations of certain heavy minerals, the threshold for primarily density-driven sorting probably lies between the specific gravity of a less dense mineral (ilmenite, 4.7) and Garnet almandine (4.3), the most common transparent heavy mineral. The number of laminations and concentrations of heavy minerals vary between trenches on the overwash terrace and appear to be controlled by their distance from sediment sources. The trench with a greatest number of laminations and higher heavy mineral concentrations is located furthest from the main dune but is just 10 m inland of a relict dune that acts as the primary source of sediment of the washover deposit in this trench. A conceptual model for heavy mineral layer deposition is presented based on geomorphological and sedimentological evidences allowing the definition of a density threshold.

New York↗
USGS1977

Seed production, seed populations in the soil and seedling production after fire for two congeneric pairs of sprouting and nonsprouting chaparral shrubs

A study of seed production, seed storage in the soil, and seedling production after fire was undertaken for a sprouting and a nonsprouting congenerica pair of species of Ceanothus and Arctostaphylos. All species exhibited large fluctuations in annual seed production. There was a significant correlation between fruit production and precipitation in the previous year. It is hypothesized that high carbon gain in years of high precipitation results in high numbers of floral primordia which, in these species, remain dominant until the following year. It was also noted that high fruit production was not dependent upon high precipitation the same year; suggesting that the fruits were utilizing carbon stored from the previous year. All 4 species were capable of producing more seeds in a single season than were stored in the soil. Apparently the soil seed pools do not represent a steady accumulation of seeds in the soil but rather are the result of dynamic fluctuations in seed inputs and outputs. Each species also had more seeds in the soil, by several orders of magnitude, than seedlings after fire in an adjacent burned stand. The sprouting and seeding productive strategies are quite different in the two genera. The information from this study coupled with that from other studies indicate 4 reproductive modes: sprouting and seedling production (C. leucodermis), abundant seedling production (C. greggii), low seedling production but better "equipped" seedlings (A. glauca), and predominantly sprouting (A. glandulosa).

Ecology↗
USGS2009

Demographic structure of California chaparral in the long-term absence of fire

Demographic structure of 12 chaparral sites unburned for 56 to 120 years was investigated. All sites were dominated by vigorous shrub populations and, although there was colonization by seedlings of woodland tree species in several stands, successional replacement of chaparral was not imminent. Although successional changes in community composition were evident, there was no indication of a decline in species diversity. Non-sprouting species of Ceanothus suffered the greatest mortality at most, but not all, sites. Sprouting shrubs, such as Quercus and Heteromeles had very little mortality, even in stands more than a century old. All postfire resprouting species had multiple stems of different ages indicating these shrubs were capable of continuously regenerating their canopy from basal sprouts. Ceanothus populations were highly clumped and there was a significant correlation across all sites between variance/mean ratio and percentage mortality. As Ceanothus populations thinned, they became less clumped. In mixed chaparral stands, Quercus and Heteromeles were significantly taller than associated Ceanothus shrubs and overtopped the Ceanothus ; at two sites, the density of live Quercus per plot was correlated with the density of dead Ceanothus. Thus, mortality of Ceanothus stems is likely related to both intra and interspecific interations. Seedling recruitment was observed for most shrub species that regenerate after fire by resprouting; seedling and sapling densities ranging from 1000–36 500 ha -1 were recorded for Quercus dumosa, Rhamnus crocea, Prunus ilicifolia, Heteromeles arbutifolia and Cercocarpus betuloides. For all but the last species, seedlings and saplings were most abundant beneath the canopy cover and not in gaps. Across all sites, recruitment was significantly correlated with depth and bio-mass of the litter layer. Cercocarpus betuloides was present in several stands, but seedling establishment was found only in one very open, disturbed stand. Regardless of stand age, taxa such as Adenostoma, Arctostaphylos and Ceanothus, which recruit seedlings after fire, had no significant seedling production.

Journal of Vegetation Science↗
USGS1999

Prescribed fire effects on biological control of leafy spurge

The flea beetle, Aphthona nigriscutis Foudras, is a potentially useful agent for biological control of leafy spurge ( Euphorbia esula L.) in grasslands devoted to wildlife conservation. However, effects of other grassland management practices on the persistence and dynamics of flea beetle populations are not well understood. We conducted small plot tests to evaluate 1) the effect of prerelease burning on establishment of A. nigriscutis colonies, and 2) the ability of established A. nigriscutis colonies to survive prescribed fire. More colonies established on plots that were burned prior to beetle release (83% establishment) than on unburned plots (37% establishment), possibly due to litter reduction and baring of the soil surface. However, most colonies established with the aid of fire did not survive past the first generation unless the habitat was otherwise suitable for the species, and we conclude that the primary benefit of prerelease burning is increased recruitment of A. nigriscutis during the first few generations. Established colonies were not harmed by burns in October and May. Both spring and fall burns resulted in an increase in leafy spurge stem density during the first growing season, but stem density declined to the preburn level by the second growing season.

Journal of Range Management↗
USGS2025

Living with wildfire in Estes Valley Fire Protection District, Larimer County, Colorado: 2023 Data report

Homeowner wildfire risk mitigation and preparedness are critical components of community wildfire readiness. This report describes the data collected through two efforts conducted in the Estes Valley Fire Protection District of Larimer County, Colorado, study area: (1) parcel-level rapid wildfire risk assessments performed by trained assessors and (2) homeowner surveys in which respondents provided self-assessments of their parcel-level wildfire risk. This project was undertaken to support Estes Valley Fire Protection District’s desire to enhance resident wildfire risk mitigation and evacuation planning. The household surveys also explored the social dimensions of wildfire, including understanding of wildfire risk, outreach or communication preferences, mitigation and evacuation preparedness activities, and perceptions of community risk reduction strategies. The results provide evidence that despite high levels of wildfire awareness and experience, respondents underestimate the risk on their properties as compared to a trained professional and have not completed important steps in the evacuation preparedness process. However, respondents would like more information on wildfire risk reduction via newsletters (mailed or emailed), community meetings, and in-person interactions.

Colorado↗
USGS2023

Living with wildfire in Genesee Fire Protection District, Jefferson County, Colorado: 2022 data report

Genesee Fire Protection District (GFPD) and members of the Board contacted the Wildfire Research Center (WiRē) early in 2021. GFPD serves a community of approximately 1,500 homes and 3,600 residents. The community borders the south side of I-70 and runs south up varied topography with varied vegetation to approximately 8,000 feet of elevation and is considered to be at extremely high risk of wildfire. In 2020, GFPD worked with the Forest Stewards Guild to update their Community Wildfire Protection Plan (CWPP). GFPD and WiRē collaborated to collect household-level data in an effort that is complementary to the insights provided by the CWPP. A series of scoping meetings that included the GFR Fire Board helped to build a shared understanding of GFPD’s goals, the setting, and the community.

Colorado↗
USGS2025

Assessment of active sand volumes at Rockaway Beach and Fire Island in New York and Seven Mile Island in New Jersey

Between 2018 and 2023, the U.S. Geological Survey assessed shoreface sediment availability at three Atlantic Coast barrier island study sites in support of a National Fish and Wildlife Foundation project entitled, “Monitoring Hurricane Sandy Beach and Marsh Resilience in New York and New Jersey.” The three study sites are Seven Mile Island, New Jersey, Rockaway Beach peninsula, New York, and Fire Island, N.Y. Previously interpreted geologic boundaries from shoreface geophysical surveys and data from repeat bathymetric surveys at each of the study sites were integrated to quantify the active sediment volume, or the volume of sediment that could contribute to beach and shoreline behavior over annual to decadal time scales. This report describes the methods used to calculate these volumes and the variability of active sediment volume for each survey at the three study sites. Our data show that when shoreface volumes account for varying alongshore extent of each study site, Seven Mile Island and Rockaway Beach peninsula have about 1.5 times the active sediment volume measured at Fire Island.

New York, New Jersey↗
USGS2017

Coastal bathymetry data collected in May 2015 from Fire Island, New York—Wilderness breach and shoreface

Scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center in St. Petersburg, Florida, conducted a bathymetric survey of Fire Island from May 6-20, 2015. The USGS is involved in a post-Hurricane Sandy effort to map and monitor the morphologic evolution of the wilderness breach as a part of the Hurricane Sandy Supplemental Project GS2-2B. During this study, bathymetry data were collected with single-beam echo sounders and Global Positioning Systems, which were mounted to personal watercraft, along the Fire Island shoreface and within the wilderness breach. Additional bathymetry and elevation data were collected using backpack Global Positioning Systems on flood shoals and in shallow channels within the wilderness breach.

New York↗
USGS2015

Bathymetry of the Wilderness breach at Fire Island, New York, June 2013

The U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center in St. Petersburg, Florida, collaborated with the U.S. Army Corps of Engineers Field Research Facility in Duck, North Carolina, to collect shallow water bathymetric data of the Wilderness breach on Fire Island, New York, in June 2013. The breach formed in October 2012 during Hurricane Sandy, and the USGS is involved in a post-Sandy effort to map, monitor, and model the morphologic evolution of the breach as part of Hurricane Sandy Supplemental Project GS2-2B: Linking Coastal Vulnerability and Process, Fire Island. This publication includes a bathymetric dataset of the breach and the adjacent nearshore on the ocean side of the island. The objective of the data collection and analysis is to map the bathymetry of the primary breach channel, ebb shoal, and nearshore bar system.

New York↗
USGS2003

Isopach Map and Regional Correlations of the Fire Clay Tonstein, Central Appalachian Basin

A tonstein that occurs within the Middle Pennsylvanian Fire Clay coal zone is a widespread marker bed that has been used for correlation purposes since the early 1900?s. Seiders (1965) first demonstrated that this tonstein is an altered volcanic air-fall ash deposit. Lyons and others (1992) have correlated the tonstein across Kentucky, West Virginia, Virginia, and Tennessee on the basis of mineralogical and geochemical ?fingerprinting?. The correlation of the tonstein, herein often referred to as the Fire Clay tonstein over this four-state area, and the abundance of thickness data on this tonstein permit construction of an isopach map that depicts its distribution. In general, the tonstein thins from Tennessee, where it is up to 12 inches (30 cm) thick, northeastward to central West Virginia, where it is less than 4 in. (10 cm) thick, and its preserved area is about 14,300 sq. mi. (37,000 sq. km). The preserved volume is 0.90 cu. mi or 3.7 cu. km. The compaction ratio of ash to rock is 6:1, so the original ash volume deposited in this area was 5.4 cubic miles (22.2 cubic kilometers). The trends in thickness suggest the source of the ash was a volcano in the Yucatan tectonic plate, which, had it not moved relative to the North American Plate since the Pennsylvanian, would be located in the present Gulf of Mexico, south of Louisiana. The thickness and extent of the tonstein appears to have been controlled partly by winds and partly by the surface on which it landed. Its absence in some areas indicates that the ash was not preserved, probably because it floated downstream as pumice.

Open-File Report↗
USGS2003

Using Logistic Regression To Predict the Probability of Debris Flows Occurring in Areas Recently Burned By Wildland Fires

Logistic regression was used to predict the probability of debris flows occurring in areas recently burned by wildland fires. Multiple logistic regression is conceptually similar to multiple linear regression because statistical relations between one dependent variable and several independent variables are evaluated. In logistic regression, however, the dependent variable is transformed to a binary variable (debris flow did or did not occur), and the actual probability of the debris flow occurring is statistically modeled. Data from 399 basins located within 15 wildland fires that burned during 2000-2002 in Colorado, Idaho, Montana, and New Mexico were evaluated. More than 35 independent variables describing the burn severity, geology, land surface gradient, rainfall, and soil properties were evaluated. The models were developed as follows: (1) Basins that did and did not produce debris flows were delineated from National Elevation Data using a Geographic Information System (GIS). (2) Data describing the burn severity, geology, land surface gradient, rainfall, and soil properties were determined for each basin. These data were then downloaded to a statistics software package for analysis using logistic regression. (3) Relations between the occurrence/non-occurrence of debris flows and burn severity, geology, land surface gradient, rainfall, and soil properties were evaluated and several preliminary multivariate logistic regression models were constructed. All possible combinations of independent variables were evaluated to determine which combination produced the most effective model. The multivariate model that best predicted the occurrence of debris flows was selected. (4) The multivariate logistic regression model was entered into a GIS, and a map showing the probability of debris flows was constructed. The most effective model incorporates the percentage of each basin with slope greater than 30 percent, percentage of land burned at medium and high burn severity in each basin, particle size sorting, average storm intensity (millimeters per hour), soil organic matter content, soil permeability, and soil drainage. The results of this study demonstrate that logistic regression is a valuable tool for predicting the probability of debris flows occurring in recently-burned landscapes.

Open-File Report↗
USGS2004

Emergency Assessment of Debris-Flow Hazards from Basins Burned by the Padua Fire of 2003, Southern California

Results of a present preliminary assessment of the probability of debris-flow activity and estimates of peak discharges that can potentially be generated by debris flows issuing from basins burned by the Padua Fire of October 2003 in southern California in response to 25-year, 10-year, and 2-year recurrence, 1-hour duration rain storms are presented. The resulting probability maps are based on the application of a logistic multiple-regression model (Cannon and others, 2004) that describes the percent chance of debris-flow production from an individual basin as a function of burned extent, soil properties, basin gradients, and storm rainfall. The resulting peak discharge maps are based on application of a multiple-regression model (Cannon and others, 2004) that can be used to estimate debris-flow peak discharge at a basin outlet as a function of basin gradient, burn extent, and storm rainfall. Probabilities of debris-flow occurrence for the Padua Fire range between 0 and 99% and estimates of debris-flow peak discharges range between 1211 and 6,096 ft3/s (34 to 173 m3/s). These maps are intended to identify those basins that are most prone to the largest debris-flow events and provide information for the preliminary design of mitigation measures and for the planning of evacuation timing and routes.

Open-File Report↗
USGS2007

Mass Wasting Following the 2002 Missionary Ridge Fire near Durango, Colorado, a Field Trip Guidebook

This field trip guide focuses on mass wasting following the 2002 Missionary Ridge fire near Durango, Colorado. We prepared this guide to accompany a May 4, 2006, field trip during the second Roy J. Shlemon Specialty Conference, which was held in Durango, Colorado, May 3-5. The conference, entitled Mass Wasting in Disturbed Watersheds, was sponsored by the Association of Environmental & Engineering Geologists (AEG) and the AEG Foundation. The objective of this Shlemon Conference was to bring together practitioners and researchers to define the current state of practice and identify unresolved problems with regard to the prediction and mitigation of mass wasting in disturbed watersheds. The one-day field trip begins and ends in Durango. Many of the field trip stops are at debris-flow fans around the periphery of the burn area, but one stop examines landslide activity in the burn area that initiated during spring 2005 snowmelt within a dormant, deep-seated landslide, as well as an erosion/debris-flow mitigation effort in a drainage basin above Lemon Reservoir. Also provided are descriptions of the Missionary Ridge fire, the geologic and climatic setting of the field-trip area, and the general effects of wildfire on watersheds.

Open-File Report↗